Apparatus for heating and applying asphaltic or bituminous materials.



W. C. MERRIzLL. APPARATUS.FOR HEATING AND APPLYING ASPHALTIC ORBITUMINOUS MATERIALS.

APPLICATION FI LED. APR. 1.5. 1914.

Patented Jan. 1, 1918.

STATE% PATENT @FFTQE.

WILLIS C. MERRILL, 0F BOSTON, MASSACHUSETTS.

To all whom it may concern:

Be it known that I, WVILLIS C. MERRILL, of Boston, in the county ofSuffolk and State of Massachusetts, have invented certain new and usefulImprovements in Apparatus for Heating and Applying Asphaltic orBituminous Materials, of which the following is a specification.

My invention relates to road buildin and road spraying machines, thatis, mac ines which spray liquid asphalt, or other bitu minous material,onto the roads :either in new road construction by spraying liquidasphalt, or other bituminous material, into the interstices of the roadmaterial to serve as a binder, or to give an asphaltic surface and torepair and patch roads already constructed, by spraying the asphaltic orbituminous material, on to the surface of old roads. The road sprayinmachines for building or surfacing roads or repairing the same, atpresent in use, depend either upon steam of ordinary pressure, that is50 to 80 lbs., with a temperature of about 300 F., or direct heat passedthrough tubes similar to flue tubes of a boiler to heat the materialcontained in the tank or other receptacle to liquefy the materialsufficiently to spray the liquid onto the road.

In the first instance where steam is em ployed to heat the material, themethod is ineffective, owing to the comparatively low temperature of thesteam at ordinary pressures, used to raise the contained mass (1' uidasphalt, or other bituminous materialig to the temperature required.

In the second instance where direct heat is passed through flues orotherwise directly communicated to the contained mass, the method isundesirable, as it is attended with more or less danger of injury to thematerial heated in the tank, owing to the high temperature of the directheat, as it is a well-known fact, that asphaltic base, or-

bituminous road materials, carbonize at tem per-atures easily reached bydirect heat, and where direct heat is used it is difficult of control,as the temperatures range higher than the danger point of carbonizationin the contained mass.

The carbonizing of the heated mass in the treating tank tends todisintegrate the asphaltic or bituminous material, and to reduce thecohesive and resilient qualities thereof when applied to the road.

The mass of the liquid asphalt, or other Specification of LettersPatent.

Patented Jan. 1, 19318.

Application filed April 15, 1914. Serial No. 831,922.

bituminous material, has great cohesion of its particles and does notfreely circulate, and said materials also have great density, whichprevents heat from rea ily permeating the same.

The direct introduction of -steam to the main or treating tank, eitherintentionally or through leakage in steam coils, when containingasphaltic or bituminous material used in road construction, is usuallyaccompanied by serious trouble from the foaming effect of moisture inthe steam, and the use of steam to liquefy asphaltic or bituminousmaterial for road building is open to the objection that too highpressures have to be carried consistent with safety, for the purpose ofraising the temperature of the asphaltic material so as to liquefy thesame to a degree sutlicient to apply it in a spray. The objection tothis high steam pressure is, first, the difficulty of keeping the steamjoints tight, and the further objection to the introduction of steam andwater by leakage into the asphaltic mass while it is heating, whichcauses it to foam. This emulsifies the material and causes it to expandand boil over and when it is applied to the road causes the liquidasphalt to froth. This foaming of the liquid asphalt prevents a goodapplication of it to the road because the liquid material leaving thespray nozzle is frothy and not a continuous free flowing liquid. Whensuch high pressures are used it becomes a danger in the hands ofcareless workmen and a menace in passing through the streets. These highpressures also necessitate the use of very heavy boiler plate which addsto the weight and expense of the apparatus.

In carrying out my invention both of these objectionable methods abovereferred to are avoided, and it is possible in my machine to obtain ahigh temperature, 450 F. or more, within the limits of safety withoutinjury to the material, due to carboniza- ,tions, foaming, etc.

liquids of light gravity, as the mass chills very easily and defeats thepurpose of spraying effectively, both as to penetration and facility ofapplication. By penetration it is understood that the asphaltic orbituminous material penetrates under pressure, or by natural causes, theinterstices in the road material, and by its cohesive properties, theasphaltic or bituminous material then binds the road material togetheron cooling.

The main object of my invention therefore is to produce a machine inwhich there is secured as high a temperature within the limits ofsafety, as regards the injury to the material to be applied, as ispracticable and economical, and to make an application of the materialto the road surface, to which the material is to be applied, at as higha temperature as it is possible to secure, without danger ofcarbonization and injury to the material to be applied.

This and other objects are attained by the mechanism hereinafterdescribed and particularly pointed out in the claims.

In operating my machine I introduce:

(a). The liquid asphalt or other bituminous material at a temperatureranging from 125 F. to 200 F. or more, from a stationary heating storageor supply tank into a tank on the machine through a suitable inlet, andthe material is then heated in the tank as described below to the propertemperature by the means therein described, and the material when soheated is distributed through suitable outlet and spray pipes onto theroad under pressure. Or,--

(6) The asphaltic or bituminous material may be introduced in a solid orsemi-liquid form into the tank, without preliminary heating, andgradually heated to melting point in the tank by the same device asdescribed herein, and then raised to the required temperature by thesame means, thus avoiding the use of the preliminary heat ing or supplytank. After the material has been introduced into the tank the inlet isclosed and heat applied through suitable conductors and a heatedcirculating medium employed to raise the temperature of the containedmass in the tank to 350 F., more or less, and to keep it in a liquidcondition. A circulating pump or other circulating mechanism is employedto keep this heating medium in constant motion and in its transit it isbrought in contact with high temperatures such as would be produced byburning fuel oil, kerosene, gas or other heat producing material, andthe circulating medium is advanced or pushed forward by the circulatingpump and the heat units stored in this mediumare transferred to the massof lower temperature contained within the tank. The advantage of thiscontinuous circulation consists in using a medium that does not condenseat a low temperature and does not concentrate the heat applied so as tocarbonize the material under treatment because the heat units stored inthis medium are under control and the temperature of the medium at notime reaches a point that injures the. integrity of the'contained massin the tank. Any suitable, hand-operated control, or thermostat may beused to regulate the degree of temperature that may be desired.

This method of a self-contained circulat ing medium offers advantages inthe facility with which it is possible to heat the contained mass in thetank, as a heat producer, like fuel oil or kerosene, can be utilized toheat the contained mass in the tank during transit from loading stationto point of application so that when the machine reaches its destinationthe work of application can begin at once if desired, as theliquidasphalt, or bituminous material. is in the desired condition to bereadily applied.

To expel the contained material in the tank under pressure I employ airat from 3to 5' atmospheres, that is, I employ free air compressed from 3to 5 atmospheres. The common appliances for controlling the pressure areemployed. This compressed air enters the closed tank preferably havingfirst passed through an auxiliary tank in which it is stored and theexcess air from the auxiliary tank passes over into the main tank. Uponopenin the outlet valve the contained mass being under this pressureimmediately passes the outlet through the line of pipe to the spraynozzles.

After the mass has been raised to the required temperature, hotcompressed air contained in the tank which is at a temperature of theinclosed mass is admitted through an outlet pipe to the sprayingmechanism to raise the temperature of this mechanism so that theoutgoing material to be applied to the road will reach the road in itsapplication at as high a temperature as possible and at substantiallythe same' temperature as in the tank. The outlet valve is inclosed in avalve box through which the circulating heating medium passes and raisesthe tem-' perature of this valve box and valve to that of the tank,which keeps the valve hot and facilitates the easy opening and closingof the valve, and also prevents the chilling or solidification of theasphaltic or bituminous material, when passing through the valve.

Suitable connections are made from the auxiliary air tank to the fueloil tank so that pressure is maintained on 'the fuel, and also asuflicient quantity of air supplied to the burner to maintain combustionas required by commercial devices in use. A suitable coil is inclosed ina heating recep tacle and is surrounded by the heat generated by themeans necessary to heat the circulating medium contained in the coil.The medium circulating through th s coil is emme heated by being broughtin contact with the heat produced by the heating device and this heat istransmitted to the mass Within the perature,

tank by means of the circulating coils arranged in the tank.

I claim for this machine an original device for heating solid orsemi-liquid asphalt, or bituminous material, to temperatures at whichthose materials must be applied in bituminous road construction andrepair by means of a heat medium which is liquid and easily controlled,and capable of being heated to the exact temperature which it isnecessary to give this asphaltic or bituminous material when applied tothe road, so that this heating medium will heat the asphaltic orbituminous material to that tembut will not during that process applyexcessive heat to it in any part 'to injure the asphalticor bituminousmaterial 7 by overheating any part before themass has attained theuniform temperature required.

A great advantage in using a heating medium having a higher boilingpoint than water lies in the fact that by this means I arm able toconvey the heat required without vaporization, and it is possible to geta higher temperature than it is practicable to get with steam. Thefurther advantage of using a fluid with a high boiling point is thatmore heat units are stored and delivered in a given time withoutcondensation loss; also the freedom from excessive pressure removes thedanger attending the use of steam as a heating medium.

In the accompanying drawings which illustrate a construction embodyingmy invention':

Figure 1 is a side elevation of the apparatus partly broken away to showinterior parts.

Fig; 2 is an enlarged detail view of the valve which controls the flowof liquid asphalt, or other bitumiilous material, from the tank to thespraying head and thence to the road.

Fig. 3 is a detail sectional view of the thermostatic device hereinafterdescribed.

Like characters of reference refer to like parts in both views.

The motor truck A is of any desired contion, the tank B receives liquidasphalt, or other bituminous material at a temperature of 150 to 200 F.or more. The asphaltio or other bituminous material may also beintroduced in a solid or semi-liquid form into the tank and then raisedto the required temperature by the same means. This material by anysuitable connection passes through a strainer or perforated basket Bsecured in place in the nozzle C closed by a suitable cover B which issecured in place in any suitable manner after the liquid asphalt, orbituminous material, has reached the desired height in the tank B. B isa suitable manhole cover.

From a suitable source, as the expansion tank N and the pipe N, a pumpor other circulating medium E receives a liquid medium having a higherboiling point than 212 F. which is circulated and heated to raise thetemperature in the tank B. This pump E forces this heating mediumthrough the pipe E into the valve box L and out from the valve box L tothe pipe E connecting at F with the heating coil F located within theheater G. The heated medium then passes from the coil F out at F to thecoil F arranged in the tank B as a spiral coil embracing the axis ofsaid tank and located adjacent to but preferably out of contact with thewall of said tank B and then back to the pump E through the pipe E. Thisheated medium is kept in circulation through this closed circulatingconduit and brings the temperature of the contained asphaltic or otherbituminous material to about 350 F. When the coil F is full ofcirculating oil, any expansion of this oil in the said coil is providedfor.by

the usual expansion tank N into which the expanded oil flows through thepipe N. The fuel oil for the heater G is stored in a tank Gr on thetruck and is under suitable air pressure by means of the pipe Gr leadingfrom an air storage tank H connected to the pump J. This air pressureforces the oil through a pipe G to the heater G and supplies sufficientquantity of air to the burner to maintain combustion as required by suchdevices. The flame from the oil jet G passes around the baffle plate Gand then envelops the coil F and the waste products of lbs. per squareinch, dueto the friction of the heating fluid passing through the pipesand not due to the temperature of the circulating heating fluid, ismaintained in the circulating coils, all the difficulties encountered'in the use of steam are obviated and the danger of foaming is alsoentirely removed. Furthermore there is no pressurewithin the interior ofthe tank containing asphaltic material during the heating of thismaterial by this circulating oil for the reason that the heating mediumis all contained in a tight circulating coil and is kept circulating,and furthermore the expansion of the oil is taken care of by theexpansion tank N provided on the exterior of the tankv containing theasphaltic material. Now when the coil is full of circulating oil, anyexpansion of this oil in the conduit or coil is provided for by theexpansion tank N into which the expanded oil flows through the pipe N,and relieves the pressure in the system, so that the danger of explosionis avoided and constant supervision unnecessary.

The air pump J forces air under pressure into the storage tank H past asuitable check valve K and by a suitable hand operated valve H and checkvalve H located in the pipe H, the compressed air passes through thepipe H to the nozzle C where it enters the top of the tank B and exertsa pressure on the top of the liquidasphalt, or other bituminousmaterial, contained in the tank. A pipe L leads froin the bottom of thetank B to the valve L (Fig. 2) and from. the valve L there leads a pipeL to the spray head L and spray nozzle L from which the 80 material issprayed on to the road. This valve L is located in the valve boX L of ansuitable construction and arrangement and said valve L is kept heated bythe hot cir culating medium passing into and through the surroundingvalve box L forming a part of the closed circulating conduithereinbefore described. This heating of the valve keeps it in conditionso that it can be readily operated and especially in cold weather whenotherwise the asphaltic or bituminous material to be applied on the roadwould be chilled or solidified by coming in contact with the cold valveand pipes before reaching the sprayers. By means of the spiral coil Fthe heating medium is circulated around and through a large proportionof the contents of tank B and heat is radiated from said coil F primarily to the peripheral portion of said contents which is desirable inview of the shape of said tank B and of the fact that as such contentsare lowered in such tank the pcripheral portions thereof follow theextensions of the pipe coils and receive heat therefrom. Sucharrangement of pipe F also supplies a very practical means for supplyingheat to the air in the upper portion of the tank B.

A dome L having a suitable safety valve L for preventing damage fromsuch pressure is connected to tank B at its top. From the casing of thissafety valve there leads apipe L which connects with and opens into thepipe L through a suitable nozzle F 66 and by means of which thisdischarge pipe L can be heated to a condition to facilitate the flow ofthe liquid road material to the spray nozzle L from which it is sprayedor delivered on to the road. Asuitable hand operated valve L is locatedin this pipe L for controlling the same when desired. The valve L whichcontrols the flow of .the liquid asphalt, or bituminous material, fromthe tank to the spray nozzle L under the air pressure previouslydescribed has a stem M to which is connected at M a lever to M pivotedto a suitable support M and M and its lower end, M is pivotallyconnectedat M to the connecting rod or link VI, which in turn is pivotallyconnected to the lever M pivoted to the frame at M and provided withasuitable foot treadle M for the attendant. A suitable compressionspring M is located around the movable rod M sl-idv able in the lowerend of the bracket M and said spring M normally tends to close the valveL at all times excepting when the foot treadle M is depressed by theattendant to open the valve L through the connections above described.The operating foot lever may be located at the rear of the machine or,any other suitable place as desired; so that in case of accident orotherwise, such as the absence of the attendant, the valve L is keptclosed and no liquid asphalt, or bituminous material, can flow exceptingwhen desired and thus waste of the material is avoided.

As a means for heating the air leading from the top of the tank B to thedischarge outlet pipe, L, it may be passed through a 10 coil P in thetop of the gas heater G where the air is heated and passed from the coilout through the pipe L to the nozzle L" where it is discharged into thedischarge pipe L to heat the same to facilitate the flow of the liquidto the spray nozzle L".

Located at any desired point in the conduit or pipe E through which thecirculating heating fluid circulates is a thermostat 0 operating thevalve 0 in the valve joint O and controlling the supply of fuel from thetank G through the gipe G to the burner G of the oil heater The objectof this thermostat is to regulate the temperature of the circulatingfluid so that it will not'rise above a predeter mined oint, at whichpoint the asphalticor other bituminous material liquefies to a properdegree or attains a temperature at which it is proper to apply to thesurface of the road.

This thermostatwhich may be set at a predeterminedpoint, say 450? F.will prevent the temperature of the circulating heat- .in medium risingabove this point which brings the temperature of the material undertreatment in the tank to about 350 F., which is about the point' wherethe asphaltic or other bituminous material liquefies to a proper degreeto be applied to the road, and this means of preventin the temperaturerising above this point Keeps the mass at the desired temperature. Now,

if the temperature of the circulating fluid a or the mass heated by thefluid should fall below the desired temperatures the operation of thethermostat is to release fuel to the burner and raise the temperature.In other words, the valve operated by the thermostat opens or closesdepending upon the temperature of the circulating heating fluid.

The principal object obtained by this thermostatic control, is that themass to be heated never rises above the regulated temaaperature withinthe limits of safety to the asphaltic or other bituminous material.

In practice by this method no material loss of this circulating heatingmedium of high boiling point occurs, as the temperature at whichvaporization would take place is not approached, and the heating me iumbein a non-elastic liquid differs from a con ensable elastic fluid likesteam.

While I have described my invention as especially adapted to thetreatment of asphalt for road work owing to the high temperaturenecessary to properly liquefy for road application, yet it will beunderstood that my invention may be used with equal facility on othersubstances suitable for road making or repairing or other uses andpurposes, such as coal tar, asphaltic oils, molasses, and other viscousmaterials which require heating to properly liquefy the same for roadbuilding or other uses and purposes, and although these last namedsubstances .do not require the high temperatures necessary with theasphalt, yet the advantages of my method of heating will be manifest toone skilled in the art, for various purposes, such as storage tanks,tank cars and tank ships, from which the material liquefied or renderedless viscous by my method of heating is adapted to readily dischar eowin to its fluidity.

I not limit myself to the arrangement or construction shown, as the samemay be varied without departing from the spirit of my invention.

Having thus described the construction embodying my invention, what Iclaim and now desire to secure by Letters Patent in the United States,I31?- 1. In an apparatus of the character described, a receptacle forasphalt, bituminous or other materials requiring heat to render themliquid or less viscous and provided with an inlet and with a dischargeoutlet, a valve controlling said discharge outlet, a source of heatingfluid having a boiling point above 212 F., a continuous conduit passingthrough said receptacle and includmg in its circuit said dischargeoutlet an d through which conduit said heating flu d 1s circulated,means for heatlng said circuscribed, a closed lating heating fluid toraise the temperature of the viscous material in the receptacle to heator liquefy the said material and to heat the discharging material, andmeans for cirrczlulating said heating fluid through said conuit.

2. In an apparatus of the character described, a receptacle for asphalt,bituminous or other materials requiring heat to render them liquid orless viscous and provided with an inlet and with a discharge outlet, avalve controlling said discharge outlet, a source of heating fluidhaving a boiling point above 212 F., a continuous conduit passingthrough said receptacle and including in its circuit-said dischargeoutlet and through which conduit said heating fluid is circulated, meansfor heating said circulating heating fluid to raise the temperature ofthe viscous material in the receptacle to heat or liquefy the saidmaterial and to heat the discharging material, means for circulatingsaid heating fluid through said conduit, and means for applying apressure to the material in said receptacle above that of the atmosphereso as to force the material from the receptacle through the saiddischarge outlet.

3. In an apparatus of the character described, a closed tank forasphalt, bituminous or other materials requiring heat to render themliquid or less viscous and provided with an inlet and with a dischargeoutlet, a valve controlling said discharge outlet, means for applying apressure to the material in said tank above that of the atmosphere so asto force the material in said tank through the said discharge outlet, asource of heating fl lid, a continuous conduit through which saidheating fluid is circulated for raising the temperature of the viscousmaterial in the tank to liquefy or I render the material less viscous,means for 1 heating said circulating heating fluid, a valve box includedin sald conduit and surrounding the discharge outlet valve so as to heatsaid valve by the said circulating heating fluid, and means located onthe exterior of said valve box for opening and closing said valve.

4. In an apparatus of the character detank for asphalt, bituminous orother materials requiring heat to render them liquid or less viscous andprovided with an inlet and with a discharge outlet, a valve controllingStudd15- charge outlet, means for applying a pressure to the material insaid tank above that of the atmosphere so as to force the material i' .1the tank through the'said discharge outlet, a source of heating fluid, acontinuous conduit through which said heating fluid is circulated forraising the temperature of the viscous material in the tank to liquefyor render the material less viscous, 180

outlet, a valve controlling said dischargemeans for heating saidcirculating heating fluid, a valve box included in said conduit andsurrounding the discharge outlet valve so as to heat said valve by thesame circulating heating fluid, and means located on the exterior ofsaid valve box for opening said valve and for automatically closing,said valve.

5. In an apparatus of the character described, a closed tank forasphalt, bitumi-- nous or other materials requiring heat to render themliquid or less viscous and provided with an inlet and with a dischargeoutlet, a valve controlling said discharge outlet, means for applying apressure to the material in said tank above that of the atmosphere so asto force the material from the tank through the said discharge outlet, asource of heating fluid, a continuous conduit through which a heatingfluid having said boiling point higher than 212 F. is circulated forraising the temperature of the Viscous material in the tank to liquefyor render the material less viscous, means for heating said circulatingheating fluid, and a valve box included in said conduit and surroundingthe discharge outlet valve so as to heat said valve by the saidcirculating heating fluid. a

6. In an apparatus of the character described, a closed tank forasphalt, bituminous or other materials re uiring heat to render themliquid or less vlscous andprovided with an inlet and with a dischargeoutlet, a valve controlling said discharge outlet, means for applying apressure to the material in said tank above that of the atmosphere so asto force the'material from the tank through thesaid discharge outlet, asource of heating fluid, a continuous conduit through which a heatingfluid having said boiling point higher than 212 F. is circulated forraising the temperature of the viscous material in the tank to liquefyor render the mateial less viscous, means for heating said circulatingheating fluid, a valve box included in said conduit and surrounding thedischarge'outlet valve so as to heat said valve by thesaid circulatingheating fluid,'and means adapted to control the supply of fuel to theheater upon the temperatureof the heating circulatingfluid reaching apredetermined point.

7. In an apparatus of the character described, a closed tank forasphalt, bituminous or other-materials requiring heatto render themliquid or lessviscous and provided with aninlet and with a dischargeoutlet, means for applying a pressure to the material in said tank abovethat of the at mosphere so as to force the material from the tankthrough the said discharge outlet, a source of heating fluid, acontinuous con- -means for applying a pressure to the mateduit throughwhich a heating fluidhaving said boiling point higher than 212 F. iscirculated for raising the temperature of the viscous material in thetank to liquety or render the material less viscous, means for heatingsaid circulating heating fluid, a valve box included in said conduit andsurrounding the discharge outlet valve so as to heat said valve by thesaid circulating heating fluid, and automatic means adapted to controlthe supply of fuel to the heater upon the temperature of the heatingcirculating fluid reaching a predetermined point.

8. In an apparatus of the character described, a receptacle for asphalt,bituminous or other materials requiring heat to render them liquid orless viscous and provided with an inlet and with a discharge outlet, aValve controlling said discharge outlet,

means for applying a pressure tothe mate- .atmosphere'so as to force thematerial'from the receptacle through the said discharge outlet, a sourceof heating fluid supply, a continuous conduit through which said heatingfluid having a boiling point above 212 F. is circulated for raising thetemperature of the material in the receptacle to heat or liquefy thesaid material and including in its circuit the said discharge outlet toheat the discharging material, means for heating said circulatingheating fluid, means included in said conduit and in the path of thesaid circulating heating fluid for circulating said heating fluidthrough said conduit, and a valve box included in said conduit andsurrounding said discharge outlet valve so'as to heat said valve by thesaid circulating heating fluid; I 1 i o 9; In an apparatus of thecharacter do scribed, a, receptacle for asphalt,"bituminous 105 or othermaterials requiring heat to render them liquid or less viscous andprovided with an inlet and with adischarg'ef outlet,

a valve controlling said'disc'harge outlet,

rial in said receptacle above that of the atmosphere so as to force thematerial from the receptacle through the said discharge outlet, a sourceof heating fluid supply, a continuous conduit through which said heatingfluid having a boiling point above 212 F. is circulated for raising thetemperatureof the material in the receptacle to heat or 'liquefy thesaid material and including in its circuit the said discharge outlet toheat the discharging'material, means for heating said circulatingheating fluid, a valve box included insald conduit and surrounding saiddischarge outlet valve so as to heat said valve by the said heatingfluid, auto matic means adapted to control the supply of fuel to theheater upon the temperature of the said heating circulating fluid reach-'or other materials requiring heat to render them liquid or less viscousand provided with an inlet and with a discharge outlet, a valvecontrolling said discharge outlet, a

source of heating fluid, a continuous conduit passing through saidreceptacle and including in its circuit the said discharge outlet andthrough which said conduit said heating fluid is circulated, means forheating said circulating heating fluid to raise the temperature of theviscous material in the receptacle to heat or liquefy the said materialand to heat the discharging material, and means for circulating saidheating fluid through said conduit.

11. In an apparatus of the character described, areceptacle for asphalt,bituminous or other materials requiring heat to render them liquid orless viscous and provided with an inletand with a discharge outlet,

a valve controllin said discharge outlet, a source of heating 1 uid, acontinuous conduit passing through said receptacle and including in itscircuit the said discharge outlet and through which said conduit saidheating fluid is circulated, means for heating said circulating heatingfluid to raise the temperature of the viscous material in the receptacleto heat or liquefy the said material and to heat the dischargingmaterial, means for circulating said heating fluid through said conduit,and means for applying a pressure to the material in said-receptacleabove that of the atmosphere so as to force the material from thereceptacle through the said discharge outlet.

In testimony whereof, I have signed my name to this specification in thepresence of two subscribing witnesses, this eleventh day of April, A. D.1914.

ILLIS o. MERRILL.

Witnesses:

GERTRUDE M. MARTIN, HAROLD J. HAM.

